It has been widely applied to biochip to fix biological products, such as protein, antibody, growth factor and gene plasmid, on the solid surfaces, such as the surface of metal, ceramics and polymeric material. As the development of medical instruments, especially the emergence of drug-containing medical instrument, fixing biological products on the surface of the medical instrument has become an extensive and in-depth issue. Comparing with common protein, the antibody contained in biological product has advantages such as high stability, hard inactivation and specificity of antigen-antibody reaction and has been widely used as in vitro diagnostic reagent and has been applied to medical diagnosis. Thus, the method for firmly fixing the antibody on the surface of the medical instrument including the surface of metal and various surface of polymeric coatings without damaging the activity of the antibody has become a key scientific and technological technique.
Nowadays, the method for fixing the antibody on the solid surface generally includes chemical bonding and physical adsorption. The method of chemical bonding generally includes the steps of forming aldehyde group and carboxy group on the solid surface firstly and fixing the antibody by chemical grafting. Two key points call for solution when fixing the antibody on the solid surface: 1 firm degree of the antibody which is fixed on the solid surface; 2 the maintenance of the activity of the antibody on the solid surface. For the biochip, the most commonly used method is to form aldehyde group and carboxy group on the solid surface, such as the surface of glass, metal and plastic firstly and then fix the antibody on the solid surface by chemical grafting. This method has advantages of high firm degree for fixing the antibody well, but can reduce the activity of the antibody to a certain extent. The method of physical adsorption is simple and able to keep good activity of the antibody on the solid surface, but is hard to maintain the firm degree of the fixed antibody. Thus, how to fix these biological products on the surface of the medical instrument remains a key technical problem left to be solved.